Gregory K. Friestad
Department of Chemistry | University of Iowa
Friday, Feb. 8, 2013
1:30 p.m., SL 102
Taming Free Radicals and Carbocations for Asymmetric Synthesis of Bioactive Compounds
Carbon-centered free radicals and carbocation intermediates are commonly presumed to exhibit poor stereochemical control, and this is considered an impediment to synthetic applications. Our program challenges this notion, focusing on the discovery and application of new synthetic methods which expand the scope of asymmetric synthesis using radicals and carbocations. For example, we have discovered and developed a remarkably versatile and stereoselective Mn-mediated free radical addition reaction of alkyl iodides and N-acylhydrazones for preparation of chiral amines. The lecture will include applications of the Mn-mediated radical addition in synthetic routes to the natural products quinine (antimalarial agent) and tubulysin D (antimitotic agent), discovery of a new type of radical–polar crossover reaction, and implementation of a new strategy for 1,5-polyol synthesis.